Liquid applicators, such as sprayers, have assisted in distributing liquids or liquids including gas components to various objects. In certain applications, such as applying an agricultural substance to a field, an applicator can assist in applying the substance in an even manner so as to create a uniform coverage while at the same time not wasting a substantial amount of the substance. Agricultural applicators can include one or more distribution booms or tool bars that are long enough (e.g., 60 feet to 150 feet) to reach multiple rows of crops at one pass. Applicators can be complex and can include multiple distribution paths or flow streams from one or more storage tanks to valves or nozzles at the point of application. Faults or variations in distribution can occur at any point in the distribution lines from a main distribution point (e.g., a reservoir) to a point of application (e.g., a coulter). Typically, if a user suspects that there is a fault with the distribution system or a problem due to variation in application by the applicator, the user inspects manual gauges or other indicators disposed at various locations of the applicator. Thus, the resolution and capabilities of custom liquid applications is limited by the current liquid application apparatus and methods.